$630
The total perimeter is 42 and 42x15=630
Answer:
D. Pythagorean
Step-by-step explanation:
Given the identity
cos²x - sin²x = 2 cos²x - 1.
To show that the identity is true, we need to show that the left hand side is equal to right hand side or vice versa.
Starting from the left hand side
cos²x - sin²x ... 1
According to Pythagoras theorem, we know that x²+y² = r² in a right angled triangle. Coverting this to polar form, we have:
x = rcostheta
y = rsintheta
Substituting into the Pythagoras firnuka we have
(rcostheta)²+(rsintheta)² = r²
r²cos²theta+r²sin²theta = r²
r²(cos²theta+sin²theta) = r²
(cos²theta+sin²theta) = 1
sin²theta = 1 - cos²theta
sin²x = 1-cos²x ... 2
Substituting equation 2 into 1 we have;
= cos²x-(1-cos²x)
= cos²x-1+cos²x
= 2cos²x-1 (RHS)
This shows that cos²x -sin²x = 2cos²x-1 with the aid of PYTHAGORAS THEOREM
Answer: 751
Step-by-step explanation:
Answer:
It will take 100 songs for the monthly price of Napster to cost the same as iTunes.
Step-by-step explanation:
Let's create two equations to represent iTunes (T(d)) and Napster (N(d)):
T(d)=0.99d
N(d)=0.89d+10
In order for us to find when the two prices will be the same, let's set the equations equal to each other and solve for x:
0.99d=0.89d+10
0.1d=10
d=100
